Slack adjuster fob oar brakes



(No Model.) 2 Sheets-Sheet 1.

W. H. MARSHALL. SLACK ADJUSTER FOR GAR BRAKES.

No. 484,859. Patented Oct. 25, 1892.

(No Model.) 2 Sheets-Sheet 2.

v W. H. MARSHALL.

SLACK ADJUSTER FOR GAR BRAKES.

No. 484,859. Patented 0011.25, 1892.

UNITED STATES PATENT OFFICE.

WALDO H. MARSHALL, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE CONSOLI- DATED BRAKE ADJUSTER COMPANY, OF SAME PLACE.

SLACK-ADJUSTER FOR CAR-BRAKES.

SPECIFICATION forming part of Letters Patent No. 484,859, dated October 25, 1892. Application filed November 16.1891. Serial No. 412,067. (No model.)

To all whom it may concern.-

Be it known thatI, WALDO H. MARSHALL, acitizen of the United States, residing at Ohicago, Illinois, have invented certain new and useful Improvements in Slack-Adjusters for Oar-Brakes, of which the following is a specification.

My invention relates to that class of devices which are designed to automatically take up the slack of car-brakes to compensate for the wear of brake shoes and gearing. The approved form of these devices comprisesin combination with one of the levers and one of the rods of the brake-gear, mechanism applied to said rod and operated by the angular movementof said lever by which the effective length of the rod to which it is applied may be varied automatically.

In the practical operation of these devices it has been found that the same piston travel cannot be secured in anumber of cars, owing to variations in the arrangement of the leverages, without rearrangement of the parts of the slack-adj usting mechanism.

It is the object of my invention to provide slack-adjusters with adjustingmeansby which they can be adapted readily for use with cars having varying arrangements of their levers.

In the accompanying drawings, Figure 1 is a side elevation of a car-truck having outside brakes and showing my invention applied to one construction of slack-adjuster for said brake. Fig. 2 is a plan view of the adjusting mechanism and of a portion of the lower brake-rod, the live-lever being shown in sectional plan view. Fig. 3 is a side elevation of the parts shown in Fig. 2. Fig. 4. isacrosssection on the line 4. 4 of Fig. 3. Fig. 5 is a vertical section of a dog, showing in side elevation a pawl and a portion of a rack engaged by the pawl; and Fig. 6 shows another construction of slack-adjuster, my improvement being applied thereto.

In the drawings, A represents the live-lever of the brake-gear, having the upper brake-rod B connected thereto, and 0 represents the lower brake-rod. The slack-adjusting mechanism is actuated by the live-lever in this construction, although it will be understood that this adjuster may be worked by any other lever of the brake-gear. In the particular form shown in Figs. 1 to 5, inclusive, this slack-adjusting mechanism comprises a casting D, longitudinally slotted to receive a series of washers E, through which the rod 0 slides, said rod being provided with wings c and the washers having shoulders riding on said wings. As the rodCslides into the casting D the washers E drop off the wings c and prevent the return movement of the rod, thus virtually shortening it and taking up the slack in the brake-gear.

In order to draw the rod into the casting for the purpose of permitting a new washer to drop, various means may be employed, a common means being shown in Fig. 6 of the drawings, wherein F represents an operatingrod connected to the live-leverA and bearing at its opposite end a dogf, pivoted in a box H, secured to rod 0, and the toe of which dog is made to engage the rod 0. The preferred construction, however, is shown in the pre ceding figures of the drawings, wherein I have employed, instead of the rod F, a rack G, slid ing through the box II, in which is pivoted a pawl I for engaging the teeth of the rack. In both of the forms described the angular movement of the live-lever in the application of the brake will move the'rack G or rod F, as the case may be, forward, and if the movement is sufficient to permit the pawl to ride over and engage a new tooth on the bar G or to slide the dog fthe width of a washer on the release of the brakes and the return of the live-lever a new washer will drop, thus taking up the slack. It is evident that the extent of this angular movement will depend I upon the arrangement and proportions of the levers of the brake-gear, and therefore the same piston movement cannot be secured in 0 a series of cars having varying arrangements and proportions of levers in their brake-gears if a positive and unvariable connection be made between the actuating-lever and the operating-rod of the slack-adj usting mechanism. 5

To vary the construction for each car would entail such labor and expense as would prohibit the use of the device. Therefore the prime object of my invention is to provide a variable and adjustable connection between too the actuating-lever and the operating-rod of the slack-adj uster, so that a uniform construction can be employed for all cars and the extent of the piston travel regulated for each car by a simple adjustment at the time of the application of the device to that car. This adjustable connection. may be made in the following manner: The ,rod F or rack G is slotted, as at L, for the reception of the pin K, carried by the lever A, and carries setscrew M, which can be adjusted to limit the movement of the pin in the slot, and a spring, as N, has one end thereof seated against the pin K and its other end secured to the operating-rod. p

The operation of my device is as follows: Inthe released position of the brakes, as shown in Fig. 3, the pin K is at the outer end of the slot L in the end of the operating-rod. As the brakes are applied the angular movement of the lever causes the pin to travel along this slot until it comes in contact with the adjustable set-screw M, after which further movement of the lever causes the operatingrod to travel, and if the total movement of the lever is sufficient a new tooth of the rack will be engaged by the pawl, or the dog will be advanced upon the rod 0 the width of a washer. On the release of the brakes the return movement of the lever first causes the pin to return to its normal position at the end of the slot, and the remainder of the movement causes the operating-rod to travel and the rod 0 to be drawn in sufficiently to permit a washer to drop. If the proportions of the brake-gear are such that with the required piston travel the movement of the pin K is greater than is necessary to drop a washer, the excess movement of the pin K can be provided for by permitting it to travel in the slot, as described, and the amount of this travel can be regulated by the screw to suit the varying conditions on diiferent cars.

The spring N is provided for the purpose of preventing the actuating-rod from moving forward during the application of the brakes until it is pushed forward by the contact of the pin K and the set-screw M, thusguarding against the possible eifect of the vibration of the car-truck. In some forms of adjusters this spring might be unnecessary. For instance, in the case shown in Fig. 6 the coil-spring in the box H might be made to serve the same purpose.

I do not intend, of course, to limit my invention to the form of slack-adjuster shown and described, nor to the precise construction and arrangement of the parts of the adjusting mechanism claimed.

I claim- 1. The combination, with the operating-rod of a slack-adj uster for car-brakes and an actu-. ating-lever for said rod, of an adjustable connection between said lever and said rod, substantially as described.

2. The combination,with the operating-rod of slack-adjusters for car-brakes, of an actuating-lever for said rod, said rod and said lever having a sliding connection, and means for limiting the sliding movement of said parts with relation to each other, substantially as described.

3. In a slack-adjuster for car-brakes, the combination, with the actuating-lever thereof and an operating-rod therefor, of means for operatively connecting said lever and said rod in difierent positions, substantially as described.

4. In a slack-adjuster for car-brakes, the combination, with a lever of the brake-gear and one of the brake-rods having wings there'- on,of a series of washers riding on said wings and through which said brake-rod slides, a rack-bar pivotally connected to the actuatinglever and sliding through a box carried by said rod, and a pawl engaging the teeth of the rack and adapted to lock it with the box, substantially as described.

5. In a slack-adjuster for car-brakes, the combination, with a lever of the brake-gear and one of the brake-rods having wings thereon, of a series of washers riding on said wings and through which said brake-rod slides, a rack-bar having an adjustable connection with the actuating-lever and sliding through a box carried by said rod, and a pawl engaging the teeth of the rack and adapted to lock it with the box, substantially as described.

6. In a slack-adjuster for brakes, the combination, with mechanism for taking up the slack, of an operating-rod for actuating the take-up mechanism and a lever for actuating the operating-rod, said rod and lever having an adjustable connection whereby the operating-rod may be arranged or adjusted for different degrees of movement of its actuating-lever, substantially as and for the purposes specified.

7. In a slack-adjuster for brakes, the combination, with mechanism for taking up the slack, of an operating-rod for actuating the take-up mechanism, a lever for actuating the operating-rod, said rod and lever having an elongated-slot and pin connection, and means for limiting the movement of the pin in the slot, substantially as and for the purposes specified.

8. In a slack-adjuster for brakes, the combination, with mechanism for taking up the slack, of an operating-rod for actuating the take-up mechanism, a lever for actuating the operating'rod, said rod and lover having an elongated-slot and pin connection, means for limiting the movement of the pin in the slot, and a spring for controlling the movement of the operating-rod, substantially as and for the purposes specified.

WALDO H. MARSHALL. Witnesses:

H. S. TOWLE, FREDERICK O. Goonwnv. 

